Scientists at Boston Children’s Hospital have created a COVID-19 protein vaccine based on alpaca antibodies, easier to produce and can be stored at room temperature.
COVID vaccines that are now available require cold storage and specialized manufacturing, making them difficult to make and distribute, particularly in underdeveloped countries. According to Boston Children’s Hospital researchers in PNAS, a potential vaccine could be easier to create and require no refrigeration.
This method could help fill in the gaps in worldwide vaccination coverage and could be used to develop vaccines for other diseases, according to the researchers, led by Hidde Ploegh (PhD), Novalia Pishesha (PhD), and Thibault Harmand (PhD).
The novel design, unlike current COVID-19 vaccines, is totally protein-based, making it straightforward to manufacture in a wide range of settings.
Nanobodies, generated from alpacas, and the spike protein that binds to receptors on human cells are the two main components of the virus.
The vaccine technology relies heavily on nanobodies. Because they recognise class II MHC antigens on the cell surface, they specifically target antigen-presenting cells, which are important for the immune system. These cells will then “show” additional immune cells the vaccine’s “business end,” which is a portion of the spike protein in this case—and thereby trigger a wider immunological response.
Current COVID-19 vaccines trigger the generation of the spike protein at the injection site in the body, and are anticipated to indirectly stimulate antigen-presenting cells, according to Ploegh.
“But taking out the middleman and talking directly to antigen presenting cells is much more efficient,” he says. “The secret sauce is the targeting.”
In the mice experiment, the vaccine stimulated large levels of neutralizing antibodies against the spike protein fragment, eliciting substantial humoral immunity against SARS-CoV-2. It also stimulated T helper cells, which rally other immunological defences, eliciting high cellular immunity.
Since the vaccine is a protein rather than a messenger RNA like the Pfizer/BioNTech and Moderna vaccines, it lends itself considerably better to mass production.
“We don’t need a lot of the fancy technology and expertise that you need to make an mRNA vaccine,” said Harmand. “Skilled workers are currently a bottleneck for production of the COVID vaccine, whereas biopharma has a lot of experience producing protein-based therapeutics at scale.”
This might theoretically allow the vaccine to be manufactured at a number of locations throughout the world, near to where it would be administered. The team has filed a patent and is now looking for biotech or pharmaceutical businesses to collaborate on further testing and, eventually, a clinical trial.
“It may be that initial application is something else other than COVID-19,” says Ploegh.
“This study was the proof of concept that our protein-based approach works well.”
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